Gas charging apparatus and method



N. E. SPIESS, JR.. EI'AL 2,857,935

GAS CHARGING APPARATUS AND METHOD Oct. 28, 1958 4 Sheets-Sheet 1 FiledMarch 14, 1956 NEWTON E. HEN RY L 4 v f/le/r A 7' ram/e x5.

O t, 28, 1953 N. E. s nzss, JR.,, ETAL GAS CHARGING APPARATUS AND METHOD4 Sheets-Sheet 2 Filed March 14, 1956 INVENTORS. NEWTON E. SPIESS,JR. aHENRY HENZE 2 MAN ATTORNEYS.

Oct. 28, 1958 N. E- E R, ETA!- 2,857,935

I GAS CHARGING APPARATUS AND METHOD Filed March 14, 1956 4 Sheets-Sheet35 FIG. 4.

I I DRIFT START CIRCUIT 6|. I i L Q.| I

L HOLD cmcuw CLOSED I L \..r VALVE OPEN HP. VALVE OPEN l CYCLE 360INVENTORS. NEWTON E. SPIESS,JJR. 8| HENRY L. HENZE file/r A TTORNEXSOct, 28, N'. E. SPIESS, JRQ, ETAL 2,857,935

'GAS CHARGING APPARATUS AND METHOD Filed March 14, 1956 4 Sfieets-Sheet4 /0Z TIME 1 I00 A Lu-"r Afi-ionm LIFT CAM (70) A FIGJI.

- m STAGE (LOW PRESSURE) VALVE CAM (74) OPEN F16. I2. CLO$ED J 2nd STAGE(HIGH PRESSURE) VALVE CAM(75) PRESSURE PSI FIG. 13.

2'0 MANIFOLD PRESSURE P PRES URE SI NORMAL PRESSURE CYCLE 2K); MANIFOLDPRESSURE AgNORMAL PRESSURE CYCLE IN VHV TORS.

S ARTING WITH CONTAINERS NEWTON E. SPIESS,JR. a ALREADY CHARGED ONCE YHENRY L. HENZE United States Patent 2,857,935 I I GAS CHARGING APPARATUSAND METHOD Newton E. Spiess, Jr., and Henry L.,Henze, Islip, N. Y.,assignors, by mesne assignments, to National Dairy Products Corporation,New York, of Delaware Application March 14, 1956, Serial No. 571,425 15Claims. (Cl. 141-3) This invention relates to methods and apparatus forcharging containers. In particular, it relates to methods and apparatusfor introducing gaseous substances such as whipping agents, propellantsor the like into containers capable of withstanding pressure.

A critical problem involved in the gas charging of containers,particularly those partially filled with a product which absorbs gas, isthe control of the pressures in the container during and after thecharging operation as well as the control of total quantity introduced.While charging the container, the critical pressure limitations imposedby the strength of the can must not be exceeded and, overall, thequantity of the charging medium introduced must be maintained at aprecise value if a uniform product is to be obtained. In gas-chargedwhipped cream containers, for example, a variation of 18% in the finalpressure of the charged container results in clearly perceptibledifferences in the quality of the whip, the product at one extreme ofthe range being dry and stiff and at the other extreme loose and wet. Afurther problem which is troublesome in the manufacture of containers ofgas-charged products is the possibility that a once charged containerwill find its way inadvertently into the input end of the chargingapparatus thereby subjecting that container to a second chargingoperation. Under normal circumstances, using conventional gas chargingtechniques, this can result in the rupture of the container andattendant hazards to equipment and personnel. Moreover, in certain casesthe process of charging containers results in back pressures which forcethe prod uct being charged back into the gassing system, resulting incontamination.

It is, therefore, an object of the present invention to provide animproved method and apparatus for charging containers.

It is another object of the invention to provide an improved method andapparatus for charging containers and products therein with gas wherebyprecisely controlled quantities of gas can be injected for the purposesof facilitating controlled discharge of the product. and forbeneficially altering the character of the product.

It is another object of the invention to provide a gas charging methodand apparatus whereby repeated cycling of one container through thecharging operation is unlikely to result in such severe multiplicationof internal pressures as to rupture the container and wherebycontaminating backflow is eliminated.

It is still another object of the invention to provide improvedapparatus whereby gas charging needles can be injected into containersto facilitate improved gassing operations and to decrease thepossibility of needle breakage.

A representative embodiment of the present invention is described indetail in the following specification having reference to theaccompanying drawings in which:

Figure l is a view in front elevation, partly in vertical section, of anapparatus for charging containers with gas;

. Figure 2 is a fragmentary view in transverse section N. Y., acorporation "ice through the center portion of the apparatus of Figure 1taken on the line 2-2 looking in the direction of the arrows;

Figure 3 is an enlarged view in vertical section of one of the needleguiding assemblies of the apparatus of Figure 1;

Figure 4 is a graph plotting the vertical displacement of a containerand the timing of several functions related thereto throughout one cycleof the apparatus of Figure 1;

Figures 5, 6, 7 and 8 are a succession of views in vertical sectionshowing a needle and guiding assembly of Figure 1 and an associatedcontainer passing through four stages of a gassing cycle;

Figure 9 is a diagram illustrating a gas pressure control system whichcan be utilized in the apparatus of Figure 1;

Figure 10 is a graph illustrating the action of the container platformlifting mechanism for one cycle of operation of the apparatus of Figure1;

Figure 11 is a graph having a time axis corresponding to that of Figure10 and illustrating the action of the low pressure stage of the gassingoperation of the apparatus of Figure 1;

Figure 12 is a similar graph illustrating the action of the highpressure stage of the gassing operation;

Figure 13 is a graph showing the relationship between the manifoldpressure and the internal container pressure over a charging cycle;

Figure 14 is a graph corresponding to Figure 13 showing the relationshipbetween the manifold pressure and the internal container pressureresulting from a second charging of the same container; and

Figure 15 is a schematic wiring diagram of the electrical system for theapparatus of Figure 1.

Referring now to the drawings and to Figure 1 in particular, theinvention is illustrated as embodied in a gas charging apparatusarranged to charge a plurality of containers C-1, C-Z, C-3 and C4simultaneously in a so-called batch charging technique, although it willbe understood the invention is not limited to batch charging, but can beembodied, for example, in continuous infeed fully automatic systems. Theapparatus is constituted broadly of a framework 10 supporting a tablesurface 11 surmounted by a charging or gassing head assembly indicatedgenerally by the numeral 12 and, disposed beneath the gassing head andthe table surface, lifting and valve actuating mechanism indicatedgenerally by the numeral 13 for driving a vertically movable containersupporting platform 14 and for controlling the gassing system.

The apparatus operates to raise the several containers C 1 C-4 against abattery of gassing or charging needles 15-1, 15-2, 15-3 and 15-4 tocause the latter to pierce the containers and to be disposed at asequence of different levels therein, while at the same time and insynchronism therewith, effecting predetermined gassing operations all asdescribed below.

To these ends the assing head assembly 12 includes a fixed cross head 16secured to a pair of hollow tubular uprights 17 and 18 in turn securedas by bolting to a cross piece 19 of the frame assembly 10. The chargingneedles 15-1 15-4 are respectively secured to the cross head 16 byclamping assemblies 20-1, 20 2, 2tl-3 and 204. each of which is arrangedto place the hollow bore of the corresponding needle in communicationwith a gassing manifold 21, which can if desired be furnished with a gaspressure indicator 21a visible to the operator of the apparatus. Gas isintroduced into the manifold 21 through a conduit or tube 22 whichpasses down through the tubular upright 17 to a junction 23 at which itdivides into a pair of parallel branch conduits 24 and 25 having camoperated valve means 26 and 27 respectively. The branch conduits 24 and25 come together at a second junction 28 fed by a single conduit 29adapted to be connected to a suitable source of gas. As shown in theflow diagram of Figure 9, the gas source can comprise for example aconventional gas bottle 36 working through a pressure regulator 31 and asuitable heat exchanger 32 for controlling the temperature of thecharging gas to maintain uniform charging conditions. The branch conduit2 4 can include in addition to the cam perated valve 26 a suitableaccumulator or gas reservoir 33 and a flow regulator 33a ,in the form ofan orifice plate.

Referring again to ,Figure 1, slidably mounted on the tubular uprights17 and 18 beneath the cross head 16 is amovable crosshead 34 urgeddownwardly by strong compression springs 35 and ,36 against limit stops37 and 38 which can takethe form of tension bolts threaded into thestationary cross head 16 Thus, the movable cross head 34 is adapted tobe slid upwardly as a unit through the agency of the vertically movableplatform 14 and the battery of containers C-l C-4 interposedtherebetween.

The movable cross head 34 includes a plurality of container positioningand needle guiding assemblies identified generally by the referencenumerals 39-1, 39-2, 39-3 and 39-4 and corresponding in number to thecontainers and the charging needles. The needle guiding and containerpositioning assemblies are all identical, With the assembly 39-4 .beingillustrated in detail by the sequential Figures -8. Also, an enlarged,fragmentary view of a needle guide is shown by Figure 3. Referring toFigure 5, the needle guiding and container positioningassembly39-4-comprises a depending container-engaging sleeve 40,preferably, as best seen in Figure 2, formed with an opening 40a initsside wall to admit the raised valve structure 56 (described below) ofthe containers. The sleeve 40 is formed'on itslower edge with a lip 41bevelled and shouldered to receive the margin of the upper end of thecontainer C-4. Formed along the axis of the sleeve 40 is a cylindricalboss 42 through which extends the lower and gently tapering tip 43 of aneedle guiding member 44, also seen in Figure 3.

The needle guiding member 44 is preferably formed of plastic, nylonhaving been found to be very suitable. The shank of the plastic memberis formed with a radially enlarged portion 45 adapted to be clampedbetween flats 46 and 47 formed respectively on the cross head and athreaded gland 46, the latter being threaded onto an upstandingcylindrical sleeve or boss 49 also carried by the cross head 34. Thegland is formed with an enlarged aperture fit) through which the upperend 51 of the guide member 44 projects with clearance on all sides toafford limited radial motion. The needle guiding member is formed with acentral through bore 52 which slidably receives the stationary gassingneedle 15-4. In this fashion, the cross head 34 can be raised by therising bat tery of containers and lowered by the springs 31 as thecontainers withd-raw,-with the needle sliding through correspondingthrough bores 5'2 in the needle guiding member 44. it has been foundthat bending beyond tolerable limits of the costly charging needles canbe controlled by means of this construction, which causes the bending orflexing to be distributed over a relatively large needle length withinits elastic limits. Also, the needle is strengthened for that part ofthe operating cycle at which strains are greatest.

The structure of the containers C-l C-4 can be generally conventional,including a cylindrical body portion 53 (Figure '5), a domed bottom anda top formed at its center with suitable aperture and wall means toreceive a valve unit 56. The valve unit 56, which can be formed, forexample, in accordance with the disclosure of the ,copendingapplication, Serial No. 211,022, filed February 1-5, 1951, now PatentNo.

4 2,761,593, dated Sept. 4, 1956, includes an inner valve head 57, anarrow stem 58 passing through the aperture in the container, and aflexible skirt or cover portion 59. The cover 59 bounds a productchamber which is vented to the atmosphere through a suitable dischargenozzle 60. In operation, .by pressing downwardly along the axis of thevalve unit '56, the cover 59 flexes and the valve .head unseats allowingthe product to be.discharged under the pressure generated within thecontainer. Gassing of the container through the valve unit 56 is carriedout by passing a charging needle along a puncturing axis through thecenter line of the stem 58, as can be seen in Figures 6 7 or 8. Incertain cases, as will be described 'below, the charging needle, infirst penetrating the stem, can be made to unseat the valve head 57 toopen the container to the atmosphere, thus facilitating purging ofunwanted air from the container.

The containers C1 Cl-4, .as stated above, rest on the vertically movableplatform 14, being adapted to be slid thereon from the table surface 11.Suitable positioning abutments 60-1, 60-2, 60-3 and 60-4 are fixed tothe platform 14 to facilitate the alignment of the several containerswith the axes of the corresponding gassing and charging needles 15-115-4. The containers can be placed on the platform 14 and the operationof the charging apparatusinitiated through suitable safety gate andswitch initiating mechanism forming no part of the present'invention,but disclosed in the copending applicatiomserial No. 584,501, filed May14, 1956, now Patent No. 2,792,028, dated May 14, 1957.

The platform 14 ,(Figure 1) is mounted for sliding movement verticallyon the tubular uprights 17 by means of a pair of elongated sleeves orbushings 61 and 62 .to which the platform 14 is rigidly affixed. Alsoaffixed to the sleeves 61 and-62 beneath the platform 14 1s a camfollower plate 63, the lower edge 64.0f which is engaged byaroller 65jo-urnalledbetween a pair of closely spaced plates .66 (only one ofwhich is visible in Figure 1), which plates form a lever arm 67pivotallyconnected to the frame 10 in a bearing assembly 68. Alsojournalled for rotation between the plates 66 at the free end of thelever arm 67 is a second roller 69 which rides on a cam plate 70 keyedto a rotating shaft 71 journalled in suitable pedestal bearings 71a anddriven from a speed reducing gear box 72 coupled to driving means suchas an electric motor 73. The profile of the cam 70 is such that itprovides alift pattern for the platform 14 as shown by the graphs ofFigures 4 and 10.

Also keyed to the rotary shaft 71 are a pair of cams 74 and '75 engagedrespectively by spring biased follower arms 76 and 77. The follower arms76 and 77 are respectively coupled through suitable linkage 78 and 79 toactuate the values 217 and 26, respectively, in the gas conduits 24 and25 which leadto the gassing needles. The cams 74 and constitute low andhigh pressure cams respectively with the profilesof the cam surfacesbeing plotted as a function of time at Figures 11 and 12 respectively..Lastly, there is keyed to the rotating shaft 71 a cam plate 80 engagedby a follower 81 which actuates a control switch means 82, the operationof which is described below.

Referring to the circuit diagram of Figure 15, the control circuit ofthe apparatus of Figure 1 is illustrated. The motor 73 which raises andlowers the platform 14 through the mechanism 13, is controlled by amotor starting circuit indicated generally by the numeral 83 and which,is conventional. The starting circuit 83 includes a coil 84 and aseries of normally open switches 85 and 86, 87 and 88, of which thelatter three are connected in the circuits to the windings of the motor73.

A normally open starting switch 89, which can be seen in Figure 1mounted on the table 11 to the left of the platform 14, is connectedacross the AC mains by a circuit including a conductor 90, the normallyopencontacts of the switchx89, conductors-'91 and .92 and the coil 84 inthe startingcircuit 83 of the motor 73. Bypassing the starting switch 89is a circuit including the cam operated control switch 82. This circuitincludes a conductor 93, the normally closed contacts of a manuallyoperated switch 94, a conductor 95, the normally open contacts of thecam operated switch 82, a conductor 96, the normally open switch 85, theconductor 92 and the coil 84. The manually operated switch 94 alsoincludes a set of normally open contacts 97 connected in a by-passingcircuit including conductors 98, 99 and 91 around the cam actuatedswitch 82 and the coil actuated switch 85.

In normal operation the operator places containers to be charged in themachine and initiates the operation by closing the starting switch 89.If preferred, the closing of this switch can be carried outautomatically by a guard and gate mechanism disclosed in said copendingapplication Serial No. 584,501, filed May 14, 1956. The coil 84 of themotor starting system 83 is then energized through the circuit includingthe conductor 90, the then closed contacts of the switch 89 andconductors 91 and 92. This closes the contacts of the switches 85, 86,87 and 88 and starts the motor 73. With the. motor 73 in operation, thecam 81 turns to operate the switch 82. The cam 81 is so shaped thatafter about one second of motor operation it closes the normally opencontacts of the switch 82, thereby completing a holding circuit to thecoil 84 through the conductor 93, the normally closed contacts of themanually operated switch 94, the conductor 95, the closed contacts ofthe switch 82, the conductor 86, the closed contacts of the switch 85and the conductor 92 to the coil 84. The starting switch is thenby-passed and can be released to assume its normally open position, anoperation normally carried out as soon as the platform 14 begins torise. Continuous operation of the motor 73 then occurs until the holdingcircuit is broken by the action of the cam 81 opening the switch 82.Once the circuit has been interrupted, the coil 84 is no longerenergized and the contacts 85, 86, 87 and 88 open to stop the motor.

The manually operated switch 94 can be used, for example, in servicingand cleaning the equipment. By closing the normally open contact 97, acircuit is completed directly to the coil 84, the circuit including theconductors 93 and 98, the closed contacts 97 and conductors 99, 91 and92.

To accomplish a complete gassing cycle for the containers, the platformraising cam 70 (Figure 1) together with the switch operating cam 81,rotate through one full revolution. The motor 73 is geared through thereduction gear means 72 to reduce the speed so that this cycle takesabout twelve seconds. The cams are so shaped that the platform 14 dwellsin its down position for approximately four seconds of this time. Thecam 81 is arranged to hold contacts of the switch 82 open for a periodof slightly more than one second, thus affording about a second oftravel before it closes again to commence another cycle. In this fashionaccidental momentary closing of the starting switch 89 will not initiatea cycle of the machine.

The operation of the machine to carry out the container charging methodof the present invention will now be described as applied to a Whippedcream container having reference in particular to Figures 4-14,inclusive, in which a 12 or 13 fluid ounce container C-4 is first filledby means not the concern of the present invention with 7 fluid ounces ofcream, leaving or 6 fluid ounces of air. The several gas pressure valueshereinafter described have been determined, for purposes ofillustration, for use in a whipped cream operation and in which thecontainer and valve assembly are able to endure up to about 220 p. s. i.before rupture, or as generally occurs, inversion of the concave bottom54. In Figure 4 there is plotted a graph of the positions of theplatform 14 through a complete cycle and, superimposed thereon,

indications of the timing relationship of the action of the electricalcircuit and the low and the high pressure gassing stages. The sequentialFigures 5-8 show one container in four positions of the charging cycleand Figures 10-14 show, on corresponding time axes, graphs of platformlift, low and high pressure gassing, and the pressure conditions in acontainer passed through one charging cycle and a container passedthrough two charging cycles.

A charging cycle is begun with the placement of containers on theplatform 14. As illustrated in Figure 5, the container C-4 is disposedbeneath the charging needle 15-4 and the corresponding needle guidingand container positioning assembly 39-4. With the closing of the switch89 the platform 14 rises under the influence of the cam 70, causing thecross head 34 to be forced upwardly and the needle 15-4 to be pilotedthrough the stem 58 of the valve 56 fitted in the top of the container.Prior to this portion of the cycle, which is represented by the risingline 100 in the graph of Figure 10 and also in Figure 4, the cam 74,which turns with the shaft 71, has opened the low pressure gas valve 26to initiate the flow of gas, which can for purposes of Whipping cream bea mixture of nitrous oxide and carbon dioxide, through the chargingneedle and into the container. Preferably, the charging needle includesa closely dimensioned orifice at its discharge end for efiicientmetering. The low pressure gassing cycle is shown by the pressuretimegraph 101 of Figure 11. As the platform 14 approaches its uppermostposition (Figure 7 and the section 102 of the graph of Figure 10) thelower tip of the needle guide member 43 can, if purging is desired,

be made to press against the top of the valve 56, opening the valve tothe atmosphere. This can be brought about by causing the lower edge 20'of the clamp 20-4 to bear heavily on the end 51 of the plastic guidesleeve 44. The tolerances of the valve opening motions can be increasedby the addition of a spring loaded plunger to engage the valve unit.Opening of the valve may in some cases be brought about also by thefriction of the needle entering the valve stem before the guide tip 43engages the top of the valve.

Passing the crest of the raised section 102 of the graph of Figure 10,the container is lowered slightly to reverse the direction of relativemovement between the needle and the valve to position the valve seataccurately. If more complete purging is desired the valve can be made toremain unseated or in an open position over the section 103 of thegraph, this corresponding to Figure 7. Of course, section 183 can beomitted by appropriate cam design if it is desired to seat the valvepromptly to reduce purging effects. Gas at low pressure (Figure 11)enters the container first above and then below the liquid level L whilethe platform is rising and gas at high pressure (Figure 12) enters overthe interval of the sections 102, 103 of Figure 10. If purging is beingcarried out, i. e., the valve is being held open, the initial flow ofgas forces the air present in the container above the liquid level outthrough the open valve to the atmosphere. It will be understood thateven more effective purging can be obtained by introducing gas initiallyat the high pressure value, eliminating the low pressure stage. InFigure 8, the lifting cam has turned to present a relatively long dwellrepresented by the numeral 104 on the graph of Figure 10, in whichposition the container has been lowered sufliciently to cause the needleguide 43 to become separated from the top of the valve to allow thevalve to backseat, sealing the container. At this point, the containercan be purged of air, and gas under high pressure under the control ofthe cam acting in conjunction with the valve 27, continues to beinjected into the liquid. The gas injec tion at higher pressure causesagitation of the liquid to promote rapid absorption of the gas and henceeffective whipping without creating momentarily excessive pressures inthe container. By injecting the major portion of the gas directly intothe liquid a higher percentage of gasgoes more quickly directly intosolution and the maximum instantaneous pressure occurring in thecontainer for any given final pressure is considerably lower. Containerfailures are thus reduced. It will be observed that foaming of the creamcan be made to occur While the valve is still open, with the rising foamlevel assisting in purging the combination of air and gas from the topof the container, if this is desired. In any event, the valve should beseated before foam can escape. In general, purging can be used in thosecases in which air is undesirable in the finished product and also inwhich it is desired to minimize the maximum internal pressures built upduring charging. With purging, maximum pressures have been found to beabout p. s. i. lower. The two stage gassing process of the presentinvention is, however, particularly adapted to processes in which fullpurging is not carried out because it minimizes gas losses whichordinarily occur when the valve opens during nedle insertion. With gaslosses closely controlled by using the two stage charging operationwithout the purging process, an extremely uniform product can beobtained throughout a complete run of containers.

It will be recalled that the low pressure gassing conduit 24 (Figure 9)includes both a flow regulating orifice 33a and an accumulator orreservoir 33. At the instant the low pressure valve 26 opens, thereservoir 33 which will have assumed the static pressure of the gas fromthe downstream side of the pressure regulator 31, comes almostinstantaneously into equilibrium with the manifold 21. In the presentcase, assuming containers are being charged having a pressure enduringproperty of 220 p. s. i., a gas pressure value at the downstream oroutput side of the regulator 31 of 210 p. s. i. is selected. The size ofthe reservoir 33 in relation to the size of the orifice 33a and thevolume of the conduits 22 and 24 and the manifold 21 is such that aninstantaneous pressure slightly above that of a fully charged container,i. e., about 125 p. s. i. is achieved. The orifice is sized so thatunder fiow conditions the manifold pressure remains at about thispressure. Thus, after the reservoir charges the manifold, the pressurewill be controlled by the flow through the orifice 33a. When thecontainer reaches the top position, the second or high pressure stagevalve 27 opens. While the valve 27 is open, the manifold pressure comesup to the full regulated pressure of 210 The high pressure valve 27 isclosed just as the containers begin to fall, after which time the firstor low pressure stage again becomes the controlling one. Referring toFigure 13, it will be seen that the pressure in the manifold firstestablishes itself at 130 p. s. i. and then, after the opening of thevalve 27, rises to 210 p. s. i. while the container pressure risesgradually to about 125 p. s. i. When the valve 27 closes, the firststage orifice limits the flow of gas in such way that pressure in themanifold is maintained above the container pressure and during thisperiod a very small amount of gas enters the container due to the smallpressure differential. The manifold pressure meantime falls offgradually until such time as the charging needle is withdrawn from thevalve of the containers to vent to the atmosphere, although the pressuregradient is always positive. At no time, therefore, does the containerpressure exceed that in the charging lines so that there is nopossibility of backfiew of the product into the gassing lines whichwould result in contamination. It will be observed that the springdepressed cross head 34 will remain positioned so that the needle guidemember is closely adjacent the container valve 56 while the chargingneedle 15-4 is withdrawn, thus insuring that the needle does not pullthe valve from the container.

Also, it will be observed that for the major portion of the chargingcycle, the pressure ratio across the orifice in the charging needle isnot less than 2:1. In accordance with the disclosure of the pendingapplication, Serial No. 154,062, filed April 5, 1950, now Patent No.2,723,- 790, dated November 15, 1955, this results in uniform meteringof gas into the container, and close control can be had over the ratioof gas to cream to achieve precise standards.

Refering to Figure 14 there is shown a graph of the pressurerelationships which obtain in the event a container is inadvertentlyrecycled through the machine to be charged twice, a condition whichnormally would be expected to result in either rupture of the containeror backflow of the product in the container into the gassing lines. Acontainer having a fully charged pressure of about 125 p. s. i. is firstsubjected to the low pressure gassing stage of 130 p. s. i. There beinga small pressure differential here favoring the upstream side of theneedle orifice, no flow of the product into the needle obtains. Shortlythereafter, the high pressure stage goes into operation with the openingof the valve 26 subjecting the container to a relatively long durationwith a pressure differential across the needle orifice of approximately85 p. s. i. Less agitation will of course occur than during the initialcharging. The pressure in the container will rise to a value ofapproximately 175 p. s. i. at the time of shut off of the gas flow andat no time does the internal pressure of the container exceed that inthe gas lines. The manifold pressure does not drop to the low pressurevalue of 130 p. s. i. immediately after the shut: ting off of the highpressure valve. This is the result of the action of the orifice 332afeeding gas to the manifold from a regulated source of higher pressurethan that in the containers and the action of the needle orifices tomaintain the manifold pressure. will have stored gas at 210 p. s. i.which will tend to endure until the time the needle is withdrawn fromthe container due to the fact that there is relatively little flowacross the needle orifice due to the small pressure differentialthereacross. As in the first charging'cycle, the pressure gradient ispositive throughout. In connection with the graph of Figure 14, itshould be understood that the purging operation (effected by thesurfaces of the cam 70 resulting in the curve sections 102 and 103 ofFigure 10) is assumed not to have occurred. This has been done to showthe least favorable conditions which could obtain in the operation ofthis system insofar as container pressure is concerned.

It will be apparent, however, that to carry out the purging operation ona once charged container would result in some loss of the productthrough the momentarily opened valve. As a practical matter, it has beenfound that satisfactory results and in some cases more accurate pressurecontrol can be achieved for certain products, such as whipped cream,without recourse to the purging operation before charging. To preventpurging, the cam 70 and needle guide 43 are, as stated, arranged toavoid pressing on the top of the valve 56 during needle insertion, andthe cam portion affording the curve section 103 is eliminated. Whileordinarily it is sometimes difficult to avoid some degree of opening ofthe container valve due to friction during needle insertion, gas lossescan be effectively minimized by use of the preliminary low pressuregassing stage. The use of the low pressure stage assures, however, thata backflow of cream into the gassing lines is avoided, even when acontainer is inadvertently charged twice.

While a representative embodiment of the invention has been describedabove, it will be understood that the invention can appear in otherstructural embodiments. Thus, for example, rather than a so-called batchcharging system as disclosed in which a group of containers are loadedmanually and charged simultaneously, a continuous system using an infeedconveyor can be used to carry sequentially through the charging cycle,the gassing Also, the reservoir 33" heads moving with the conveyor. Theinvention should not, therefore, be regarded as limited except asdefined by the following claims.

We claim:

1. In apparatus for charging containers with gas, a container chargingmember comprising a hollow needle, a container support spaced from theneedle, said support and needle being relatively movable to be broughttogether to cause the needle to enter a container on the support tointroduce gas therein, a needle guide normally disposed adjacent the endof the needle to support the needle against lateral movement as itentersthe container, means to mount the needle guide and needle forrelative movement axially of the needle, means to carry the needle in anaxially fixed position, means to move the container support toward theneedle, said needle guide being mounted for movement in the direction ofmovement of the support and including abutment means to be engaged by acontainer on the support to be moved thereby, yieldable resilient meansto urge the needle guide toward the support and a container thereon,means on the needle guide to engage a valve of a container on thesupport to vent the container to the atmosphere as the needle enters thecontainer, and means to pass gas into the container through the needlewhile the container is vented to the atmosphere.

2. In apparatus for charging containers with gas, a container chargingmember comprising a hollow needle, a container support spaced from theneedle, said support and needle being relatively movable to be broughttogether to cause the needle to enter a container on the support tointroduce gas therein, a needle guide normally disposed adjacent the endof the needle to support the needle against lateral movement as itenters the container, means to mount the needle guide and needle forrelative movement axially of the needle, means to carry the needle in anaxially fixed position, means to move the container support toward theneedle, said needle guide being mounted for movement in the direction ofmovement of the support and including abutment means to be engaged by acontainer on the support to be moved thereby, yieldable resilient meansto urge the needle guide toward the support and a container thereon,said needle guide abutment means including shoulders cooperative withportions of a container on the support to center the container thereonto receive the needle in a predetermined place, said needle guideincluding a sleeve to receive the needle, said sleeve including alaterally flexible end portion adjacent the container.

3. Apparatus as set forth in claim 2, said sleeve being formed ofplastic, and means to mount the sleeve in the guide for limited movementrelatively thereto radially of the needle.

4. Apparatus as set forth in claim 2, said sleeve including a portionadjacent its other end to be engaged by said means to carry the needlewhen the charging member and container support are in their mostproximate positions.

5. In apparatus for charging containers with gas, a frame, a containersupport mounted on the frame for vertical movement, a fixed cross headsupported by the frame above the container support, gassing needle meanscarried by the cross head in a depending vertical position, drive meansto raise the container support to cause containers thereon to receivethe needle means, means in the cross head to receive gas under pressureto be passed into the needle means, a movable cross head carried by theframe above the containers on the support for vertical movement, guidemeans in the movable cross head to support the charging means laterally,first and second conduit means to pass gas from a pressure source to theneedle means, a flow restricting orifice, a gas reservoir and a firstvalve in the first conduit means, a second valve in the second conduitmeans, and means operated by drive means for the container support tooperate the first and second 7 to p Y valves in timed relation to openthe first valve before the needle means enters a container and to openthe second valve after the needle means enters a container.

6. In apparatus for charging valved containers with gas, a frame, acontainer support mounted on the frame for vertical movement, a fixedcross head supported by the frame above the container support, gassingneedle means carried by the cross head in a depending vertical position,drive means to raise the container support to cause containers thereonto receive needle means, means in the cross head to receive gas underpressure to be passed into the needle means, a movable cross headcarried by the frame above the containers on the support for verticalmovement, guide means in the movable cross head to support the chargingmeans laterally, container valve operating means carried by the movablecross head to open the container valve while the needle means enters thecontainer, conduit means to pass gas from a pressure source to theneedle means, a valve in the conduit means, and means operated by thedrive means to open the valve in the conduit as the needle means entersthe container and as the container valve operating means on the movablecross head opens the container valve, thereby to purge the container.

7. Apparatus as set forth in claim 6 including means to disable thecontainer valve opening means after a predetermined interval.

8. Apparatus as set forth in claim 7, said drive means for the containersupport comprising a cam, said disabling V means for the container valveoperating means comprising a portion on the cam to lower the containersupport for a short distance;

9. In apparatus for charging containers with gas, a frame, a pair ofuprights supported by the frame, a container support slidably mounted onthe uprights, cam means to raise the container support, drive means forthe cam means, a fixed cross head carried by the uprights at their upperends, a movable cross head slidably mounted on the cross head betweenthe container support and the fixed cross head, resilient means to urgethe movable cross head downwardly, charging needle means carried by thefixed cross head, container positioning and needle guiding means carriedby the movable cross head, gas conduit means to connect a source of gasunder pressure to the charging needle means, valve means in the conduitmeans, cam means movable with the drive means to operate the valvemeans, said drive means including an electric motor, means to energizethe motor including a normally open starting switch, a normally openby-pass switch connected around the starting. switch, and cam meansmovable with the drive means to close the control switch while thecontainer support is away from its loading position.

10. In a method for gas charging a closed container through a chargingmember adapted to be brought into communication with the inside of thecontainer, the steps of establishing a first gas pressure value in themember no less than that to which the container is to be ultimatelycharged, thereby to establish gas flow from the member, bringing themember and container into charging relationship, subsequently raisingthe charging pressure in the member to a second value to increasesubstantially the gas flow into the container, and terminating thecharging operation after a predetermined interval to establish aninternal container pressure no greater than the first gas pressurevalue, by first reducing the charging pressure in the member to a valuein the vicinity of the first value, and breaking the chargingrelationship between the container and the member.

11. The method as set forth in claim 10 in which the ultimate pressureto which the container is to be charged is approximately half of therupturing pressure of the container and in which the second pressurevalue is slightly less than the rupturing pressure.

12. In a method for charging a closed container having a .quantity ofliquid therein using a charging member adapted to be brought intocommunication with the inside of the container, the steps ofestablishing a first gas pressure value in the member no less than thatto which the container is to be ultimately charged, thereby to establishgas flow from the member, bringing the member and container intocharging relationship, causing the member to discharge into the liquidin the container and raising the gas pressure in the member to a secondvalue substantially exceeding the first, thereby to discharge gas intothe liquid at an increased velocity to establish agitation thereof, andterminating the charging operation as the internal pressure approachesthe second value, by first reducing the charging pressure in the memberto a value in the vicinity of the first value, and breaking the chargingrelationship between the container and the member.

13. The method as set forth in claim 12, in which the ultimate pressureto which the container is to be charged is approximately half of therupturing pressure of the container, and in Which the second pressurevalue is slightly less than the rupturing pressure.

14. In a method of gas charging a pressure resistant container having aquantity of cream therein to be whipped by the gas and subsequentlydischarged from the container 'by the gas pressure, the container havingadischarge valve operable by inwardly directed pressure and capable ofreceiving a gas charging member, the steps of causing a gas flow fromthe member by establishing a first pressure value therein no less thantheultimate pressure to which the container is to be charged, bringingthe container and charging member together to cause the member whiledischarging gas to enter the container through the valve to dischargethe gas into the cream, moving the container and member in the oppositedirection for a short distance to seat the valve'firmly'in thecontainer, raising the gas pressure in the member to a second valueslightly below the rupture point of the con- 12 tainer to discharge gasat a higher velocity intothe cream to establish agitation thereof andentraining of the: gas thereby, reducing the gas pressure in the memberto the vicinity of the first value, and separating the member and thecontainer.

15. In a method for gas charging a pressure resistant containerpartially filled with a liquid, said container having a dischargevalveoperable by inwardly directed pressure and capable of receiving -acharging member, the steps of causing a gas flow through a chargingmember by establishing a pressure therein, bringing the container andmember together to cause the member while discharging gas to enter thecontainer through the valve to communicate first withthe space above theliquid and to open the valve, the discharging gas thereby displacing airfrom the container through the valve, causing the member to dischargethe gas into liquid to be entrained thereby, moving the container andmember relatively to one another to close the valve, introducing apredetermined further quantity of gas into the container through themember and separating the member and the container.

References Cited in'the file of this patent UNITED STATES PATENTS

